Will be incomplete for a good long while, I'll be adding things in pieces.

Merethic Era:

Early ME: Imga are said to have conquered all of Valenwood, some of Cyrodiil and Elsweyr.

Middle ME: The Aldmer settlers arrive in Haset Hyarnai, the marsh is unforgiving and many die from hostile conditions. They push on hoping that there must be something better deeper into the wilderness. They eventually get into the Elden Grove and set up shop there on the southern edges. Establishing the first settlement in Valenwood (Greenheart).

Middle-Late ME: A young Aldmer had signed Y'ffre's Green Pact, thus transforming the Aldmeri colonists into Bosmer, and the Aldmer that had signed the pact became The Silvenar. This change resulted in the Ooze mythos. The Imgan State Gat'hagoor falls. Tarboorgai becomes the de facto Imgan capital.

Late ME: Treethane Arenth Thorimil slaughters the Ayleid sorcerer-king of Olynavrien, taking many Ayleid into the tribe, and settling in and around the Ayleid kingdom. Eplear Camoran is born. Olynavrien is renamed Arenthvrien during this time. Arenth Thorimil slays the Satyr warlord Tetrarox. Arenth Thorimil marries Olivae Thorimil. Falinesti stands up out of the ground and begins walking around, causing the settlement around it to collapse into a massive sinkhole generated as a result.

ME 115: Olivae Thorimil gives birth to Riacher Thorimil.

ME ?: Olivae is kidnapped by Shagrathi Cultists, Arenth calls upon the fey to destroy their camp - Shaegravine. Arenth is named King Arenth Thorimil, the first king of Bosmer.

ME 84: King Arenth Thorimil passes away. His son Riacher Thorimil succeeds him at 31 years old.

1E 0: Eplear is crowned King of Valenwood. Codriel refuses the coronation and keeps the kingdom of Arenthia isolated from the Camoran Empire, against the advice of his siblings. Giants build the city of Haven in celebration of Eplear's coronation.

1E 1: Codriel loses his kingship and treethane status in Arenthia and the Thorimil tribe.

1E 2: Larelerva Thorimil is crowned the new Queen and treethane of Arenthia and the Thorimil tribe, Larelerva's first order of business is to strike a deal with Eplear of joint rule over the Kingdom of Arenthia. Arenthia would maintain its autonomy, but subject to Eplear's taxes.